How to Control Rust on Viburnum Trees

Viburnum (Viburnum spp.) is a large genus of deciduous and evergreen shrubs and trees. Depending on the species, viburnums grow throughout U.S. Department of Agriculture plant hardiness zones 3 through 9. These stunning plants can provide fragrant flowers and ornamental berries but are susceptible to various fungal diseases such as rust. Rust is more of a nuisance than a serious concern, but it can cause the viburnum to become vulnerable to more serious diseases and environmental factors.

1

Prune infected and damaged branches, leaves and stems from the plant with a pair of sharp pruning shears. Make cuts above the infected area cutting into healthy wood and sanitizing the shears with a diluted bleach mixture after each cut. Dispose of the infected plant matter in a garbage bag.

2

Thin the viburnum plant by removing dense foliage with sharp pruning shears. This allows for proper air circulation through the plant and for sunlight to penetrate the leaves. Sunlight and air circulation will encourage quicker leaf drying and help prevent fungal diseases.

3

Avoid overhead irrigation, which dampens the leaves and encourages spore germination. Water near the base of the viburnum during the early morning hours.

4

Prevent rust from attacking viburnum by spraying the entire plant with neem oil in the spring. Rake any plant debris that has fallen to the ground around the tree and dispose of promptly. Fallen plant matter provides the perfect hiding place for rust to overwinter.

5

Dissolve two 325-milligram uncoated aspirin tablets per quart of lukewarm water. Pour the mixture in a spray bottle and thoroughly coat both sides of the leaves and stems of the viburnum plant with the solution as an organic treatment for rust. Treat the viburnum a second time 7 days later. Apply a chemical fungicide -- such as neem oil -- if the aspirin treatment doesn't cure the rust.

Things You Will Need

Pruning shears

Bleach

Garbage bag

Neem oil

Rake

Uncoated aspirin tablets

Spray bottle

Tip

Apply fungicides -- such as neem oil -- on a calm day with temperatures between 40 and 90 degrees Fahrenheit and no rain for 24 hours.

Each type of fungicide has its own specific application instructions and warnings that must be followed to prevent unintended damage to the viburnum and surrounding plants.

About the Author

Marylee Gowans has written about gardening for both online and print publications. She attended the University of Akron, graduating with a Master of Fine Arts in creative writing. In 2009, she received master gardener certification from the Master Gardeners of Summit County, Ohio.